Project Summary Although sexual violence (SV) among youth is a critical public health issue, there are few prevention initiatives that have demonstrated long-term reductions in SV. There is increasing recognition that SV prevention efforts may be most effective if youth are central to the development and implementation of such efforts. However, to date, there are no rigorously evaluated youth-led SV prevention efforts, nor how they can be best informed by research and knowledge on prevention best practices. Further, we know little about the actual process by which youth create prevention initiatives. Teen UP (TU) is a youth-led program in Rapid City, SD that focuses on addressing a variety of public health issues, including awareness about SV. This ?homegrown? positive youth development initiative is well-integrated in the community and is the ideal platform on which additional multi-level, evidence-based SV prevention strategies can be added. Researchers and SV prevention specialists at the University of New Hampshire, in partnership with Rape Prevention Education-funded agencies in South Dakota (SD) (i.e., Network Against Family Violence and Sexual Assault and Working Against Violence Inc.) will work together along with a number of community stakeholders (e.g., educators, peers, elders), youth, and expert consultants to enhance TU to include additional SV prevention strategies including a youth prevention summit. During the Refinement and Planning Phase of the project, we will form a Research and Programming Advisory Board (RPAB); obtain data via focus groups and individual interviews with stakeholders and key informants, including youth and adults from the community; and develop a detailed enhanced prevention toolkit. Together, we will document the process of using youth-adult partnerships to create and implement SV prevention across several levels of the ecological model using a variety of strategies (e.g., photovoice, social network analysis). In addition to a detailed process evaluation, we will employ a single-case multiple baseline design as well as a matched comparison design to determine the impact that engagement with and exposure to different TU enhancement components (and dosage) has on primary (i.e., reductions in SV), intermediary (e.g., perceptions of social norms, emotion regulation), and secondary (e.g., dating violence, suicidal thoughts) outcomes among middle and high school youth. We will also examine the behavioral and attitudinal impact that the enhanced TU program has on school personnel and parents of youth. If TU is deemed effective, the products (e.g., toolkits) that result from this project can be readily disseminated to communities across the U.S. who wish to implement and sustain a theoretically-grounded, multi-level, youth-led SV prevention initiative.